Rapid fluid cooling devices and methods for cooling fluids

ABSTRACT

A cooling device includes a target fluid inlet, a target fluid outlet, an inner conduit, and a chamber surrounding the inner conduit. The inner conduit communicates with the target fluid inlet and the target fluid outlet, and provides a flow path for a target fluid to be cooled. The chamber contains a first endothermic reactant and includes a reactant inlet selectively alterable from a closed state to an open state. When the reactant inlet is in the closed state, the first endothermic reactant is isolated from a second endothermic reactant and no endothermic reaction occurs. When the reactant inlet is in the open state, the reactant inlet provides a flow path for enabling the second endothermic reactant to come into contact with the first endothermic reactant in the chamber for initiating the endothermic reaction and cooling the target fluid in the inner conduit.

CROSS REFERENCE TO RELATED APPLICATIONS

This divisional patent application claims the benefit of U.S. patentapplication Ser. No. 12/711,749, filed Feb. 24, 2010, and titled “RAPIDFLUID COOLING DEVICES AND METHODS FOR COOLING FLUIDS,” which claims thebenefit of U.S. Provisional Patent Application Ser. No. 61/154,972,filed Feb. 24, 2009, titled “RAPID FLUID COOLING DEVICES AND METHODS FORCOOLING FLUIDS;” the contents of which are incorporated by referenceherein in their entireties.

TECHNICAL FIELD

The present invention relates generally to fluid cooling devices. Moreparticularly, the present invention relates to the cooling of fluids byendothermic reaction.

BACKGROUND

The cooling of core body temperature, such as for inducing hypothermia,is a medical treatment increasingly being used to treat patients as partof various medical-related procedures. Administering cooled intravenousfluids to induce hypothermia in cardiac arrest patients in thepre-hospital setting has been found to improve the likelihood of thosepatients being subsequently discharged from the hospital neurologicallyintact. Induced hypothermia therapy has proven effective in postponingdamage to tissues caused by insufficient blood flow and oxygendeprivation. The smaller the time difference between cardiac arrest andinduced hypothermia, the higher the likelihood of successful treatment.While there are in-hospital products available for inducing hypothermia,these products are not feasible for use in the pre-hospital setting.

The cooling of intravenous fluids for use in the pre-hospital setting iscurrently achieved though the use of conventional, bulky refrigerationunits or simply ice-filled containers. Primary responders are typicallyunable to carry both conventional refrigerators and cardiac arrestpatients simultaneously on-board a vehicle (e.g., ambulance, helicopter,etc.), or at least it is impractical to do so, for various reasons suchas the space required for the refrigeration unit or ice-filled containerand the fact that induced hypothermia as a treatment will be indicatedin only a small fraction of the emergency situations encountered.Consequently, a second emergency vehicle carrying a refrigeration unitis required to intercept the primary responder and supply the primaryresponder with cooled intravenous fluids to administer to the patient.Once the cooled fluids are taken out of the refrigerator or ice-filledcontainer, the fluids immediately begin to warm and there is currentlyno method available to effectively stop the warming process.

In recent years, there has been evidence supporting the use of inducedhypothermia therapy in various other medical applications, includingcardiac surgery and stroke recovery. As more medical discoveries aremade, the potential uses of cooled fluids are likely to increase in boththe pre-hospital and in-hospital settings.

In view of the foregoing, there is an ongoing need for cost-effective,efficient, portable, and compact fluid cooling devices for use in themedical field in general, and for use in rapidly cooling intravenousfluids in particular such as for inducing hypothermia in patientsrequiring medical attention, as well as for use in various non-medicalfields.

SUMMARY

To address the foregoing problems, in whole or in part, and/or otherproblems that may have been observed by persons skilled in the art, thepresent disclosure provides methods, processes, systems, apparatus,instruments, and/or devices, as described by way of example inimplementations set forth below.

According to one implementation, a cooling device includes a targetfluid inlet, a target fluid outlet, an inner conduit, and a chambersurrounding the inner conduit. The inner conduit fluidly communicateswith the target fluid inlet and the target fluid outlet, and provides aflow path for a target fluid to be cooled. The chamber surrounding theinner conduit contains a first endothermic reactant and includes areactant inlet selectively alterable from a closed state to an openstate. When the reactant inlet is in the closed state, the firstendothermic reactant is isolated from a second endothermic reactant andno endothermic reaction occurs. When the reactant inlet is in the openstate, the reactant inlet provides a flow path for enabling the secondendothermic reactant to come into contact with the first endothermicreactant in the chamber for initiating the endothermic reaction andcooling the target fluid in the inner conduit.

According to another implementation, the reactant inlet of the coolingdevice may further include a barrier. When the reactant inlet is in theclosed state, the barrier may divide the chamber into a first regioncontaining the first endothermic reactant, and a second regioncontaining the second endothermic reactant. The cooling device mayinclude an actuator configured to open the barrier wherein the reactantinlet is altered to the open state.

According to another implementation, the cooling device includes apressure release valve adapted to communicate with the chamber, whereinthe pressure release valve allows flow from the chamber to a receptacleadapted to communicate with the pressure release valve when the pressurein the chamber increases to a predetermined critical pressure.

According to another implementation, at least a portion of the chamberis flexible such that the volume of the chamber is expandable.

According to another implementation, the cooling device includes aninsulating material surrounding the chamber.

According to another implementation, the target fluid includes salinesolution. In another implementation, the target fluid further includes atherapeutically active drug.

According to another implementation, the reactant inlet comprises afitting configured for connection to an external source of the secondendothermic reactant. In another implementation, the reactant inletcomprises a valve.

According to another implementation, an intravenous target fluiddelivery system includes an IV target fluid reservoir, a cooling device,and a cooled IV target fluid receiving tube. The IV target fluidreservoir contains an IV target fluid to be cooled in the coolingdevice. The IV target fluid reservoir fluidly communicates with a targetfluid inlet of the cooling device. The cooled IV target fluid receivingtube fluidly communicates with a target fluid outlet of the coolingdevice, and is configured for intravenously administering the cooled IVtarget fluid to a patient.

According to another implementation, the first endothermic reactantincludes an inorganic salt such as, for example, ammonium nitrate,ammonium chloride, potassium chloride, etc. The second endothermicreactant may, for example, include water.

According to another implementation, the reactant inlet includes abarrier and in the closed state, the barrier divides the chamber into afirst region containing the first endothermic reactant, and a secondregion containing the second endothermic reactant. In someimplementations, an actuator is configured to open the barrier whereinthe reactant inlet is altered to an open state. The actuator may beconfigured to puncture the barrier. Alternatively, the actuator may beconfigured to move at least a portion of the barrier to create anopening therethrough.

In some implementations, the IV target fluid reservoir may include an IVbag. The cooled IV target fluid receiving tube may include an IVcatheter.

According to another implementation, a method is provided for cooling atarget fluid. In the method, a target fluid is flowed from a targetfluid inlet of a cooling device, through the cooling device, and to atarget fluid outlet of the cooling device. While flowing the targetfluid, heat is removed from the target fluid by conducting anendothermic reaction in the cooling device.

According to another implementation, a method is provided for treating apatient. A target fluid to be cooled is flowed from a reservoir througha target fluid inlet of a cooling device, and into an inner conduit ofthe cooling device. The cooling device includes a chamber surroundingthe inner conduit and containing a first endothermic reactant. Thechamber includes a reactant inlet selectively alterable from a closedstate to an open state, wherein in the closed state, the firstendothermic reactant is isolated from a second endothermic reactant andno endothermic reaction occurs. The endothermic reaction is initiatedand the target fluid in the inner conduit is cooled by altering thereactant inlet from the closed state to the open state, wherein thereactant inlet provides a flow path for enabling the second endothermicreactant to come into contact with the first endothermic reactant in thechamber. The cooled target fluid is flowed through a target fluid outletof the cooling device into a cooled-fluid-receiving tube. The cooledtarget fluid is administered to the patient intravenously to reduce thepatient's core body temperature.

In some implementations, the target fluid includes saline solution. Infurther implementations, the target fluid further comprises atherapeutically active drug.

Other devices, apparatus, systems, methods, features and advantages ofthe invention will be or will become apparent to one with skill in theart upon examination of the following figures and detailed description.It is intended that all such additional systems, methods, features andadvantages be included within this description, be within the scope ofthe invention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood by referring to the followingfigures. The components in the figures are not necessarily to scale,emphasis instead being placed upon illustrating the principles of theinvention. In the figures, like reference numerals designatecorresponding parts throughout the different views.

FIG. 1 is a simplified perspective view of an example of a fluid coolingdevice according to the present teachings.

FIG. 2 is an exploded perspective view of an example of a fluid coolingdevice according to the present teachings.

FIG. 3 is a cut-away view of a portion of a chamber surrounding innerhelical conduits according to the present teachings.

FIG. 4 is a cross-sectional elevation view of another example of a fluidcooling device according to the present teachings that illustrates abarrier within the chamber.

FIG. 5 is a flow diagram illustrating a method for cooling a targetfluid according to the present teachings.

FIG. 6 is a flow diagram illustrating a method for treating a patientaccording to the present teachings.

FIG. 7 is a schematic of an intravenous target fluid delivery systemaccording to the present teachings.

DETAILED DESCRIPTION

By way of example, FIGS. 1-7 illustrate various implementations of afluid cooling device, a method for cooling a target fluid, a method fortreating a patient, and a related system. The various implementationsprovide a highly effective, compact, transportable, and efficientsolution for rapidly cooling a target fluid for use, as for example, inthe pre-hospital setting for intravenously inducing hypothermia orotherwise significantly reducing the core body temperature in cardiacarrest patients as well as for other medical uses and non-medical uses.As noted above, the less the difference in time between cardiac arrestand induced hypothermia, the higher the likelihood of success insubsequently discharging cardiac arrest patients from the hospitalneurologically intact. Hypothermia is defined as a body temperaturesignificantly below 37° C., and there are various levels of hypothermia.For example, mild hypothermia is defined as a body temperature of about34° C., moderate hypothermia is defined as a body temperature of about23-32° C. and profound hypothermia is defined as a body temperature ofabout 12-20° C. See Stedman's Medical Dictionary, 26^(th) Edition, 1995.A fluid cooling device consistent with the present teachings hasexperimentally demonstrated superior performance in providing a cooledtarget fluid for use in the pre-hospital setting, as compared with thecurrent method of cooling fluids in the pre-hospital setting viaconventional refrigeration. For example, a fluid cooling deviceaccording to the present teachings has experimentally cooled a targetfluid (i.e., saline solution) from room temperature to about 4° C. inabout 1.5 to 2.0 minutes, wherein ammonium nitrate and water wereutilized as the endothermic reactants in the cooling device. The coolingdevice according to the present teachings may be sized and configuredfor compatibility with associated fluid delivery components. Forexample, the cooling device may be easily connected to standardizedintravenous delivery equipment to function as an in-line, on-demandchilling device. All or part of the cooling device may be sterilizableand reusable, or alternatively may be configured as a disposablesingle-use device.

FIG. 1 is a simplified perspective view of an example of a fluid coolingdevice 100 according to the present teachings. The cooling device 100generally includes a target fluid inlet 102 through which a target fluid(e.g., saline solution) to be cooled may enter the cooling device 100,and a target fluid outlet 104 through which the target fluid may exitthe cooling device 100. The cooling device 100 also generally includes achamber 106 surrounding one or more inner conduits (not shown in FIG. 1)between the target fluid inlet 102 and the target fluid outlet 104, andcontaining a first endothermic reactant (e.g., ammonium nitrate,ammonium chloride, potassium chloride, or the like). The firstendothermic reactant may, for example, be packed into the chamber 106 inany suitable form such as powder, pellets, grains, gel, colloid,suspension, liquid, or the like, and may fill the volume in the chamber106 around the inner conduit or conduits. The inner conduit fluidlycommunicates with the target fluid inlet 102 and the target fluid outlet104, and provides one or more flow paths for a target fluid to becooled. An example of an inner conduit provided as one or more innerhelical conduits is described below with respect to FIGS. 2 and 3. Thoseskilled in the art will appreciate that the inner conduit(s) may beconstructed of various materials (e.g., medical grade metals, thermallyconductive plastics, and the like) and may include various shapes andcross-sectional areas so as to optimize the available surface area forheat transfer. The target fluid inlet 102 may generally be configured toaccommodate the size of any inlet tubing or fitting connected to thetarget fluid inlet 102. The target fluid outlet 104 may generally beconfigured to accommodate the size of any outlet tubing or fittingconnected to the target fluid outlet 104. The chamber 106 also generallyincludes a reactant inlet 108 that is selectively alterable from aclosed state to an open state. The reactant inlet 108 may include, forexample, a Luer-Lock™ port or any valve or fitting switchable betweenclosed and open states, or an openable or frangible barrier. In theclosed state, the first endothermic reactant is isolated from a secondendothermic reactant and no endothermic reaction occurs. In the openstate, the reactant inlet 108 provides a flow path for enabling thesecond endothermic reactant to come into contact with the firstendothermic reactant in the chamber 106 for initiating the endothermicreaction and consequently cooling the target fluid in the inner conduit.As in the case of the first endothermic reactant, the second endothermicreactant may be provided in any suitable form (e.g., solid, semi-solid,colloidal, liquid, etc.). Moreover, the first and/or second endothermicreactant may include any suitable additive that promotes or optimizesthe endothermic reaction.

As appreciated by persons skilled in the art, various types ofendothermic reactions exist and thus the specific reactants utilized inthe cooling device 100 will depend on the particular endothermicreaction being implemented. As examples, ammonium nitrate, ammoniumchloride, or potassium chloride may be utilized as the first endothermicreactant, and in each case, water may be utilized as the flowable secondendothermic reactant. Other flowable materials may also be suitable forserving as the second endothermic reactant. Generally, the coolingdevice 100 may employ any combination of reactants that, when combined,result in an endothermic reaction suitable for rapid cooling of aselected target fluid such as, for example, saline solution. The secondendothermic reactant may be flowed into the chamber 106 via the reactantinlet 108 by any suitable means such as, for example, utilizing asyringe (not shown) or other external source of reactant. Alternatively,the second endothermic reactant may be provided internally within thecooling device as described by example below in conjunction with FIG. 4.Those skilled in the art will appreciate that in some implementations,the first endothermic reactant may not be pre-loaded in the chamber 106.For example, both the first and second endothermic reactants may besupplied from external sources (e.g., syringes) into the chamber 106 viathe reactant inlet 108 in any order (or from two separate reactantinlets) for initiating the endothermic reaction. Having the firstendothermic reactant and/or the second endothermic reactant preloaded inthe chamber 106 may be particularly useful in implementations in whichthe cooling device 100 is utilized to rapidly cool intravenous fluids inthe pre-hospital setting, for example.

In the present example, the chamber 106 may be constructed of, forexample, PVC plastic. At each end of the chamber 106, an end plate 110may be attached to the chamber 106 by any suitable means, and may beconstructed to accommodate the ends of the inner conduits. An end cap112 may also be secured by any suitable means to the end plate 110and/or chamber 106 at each end of the chamber 106. The end caps 112 maybe tapered or otherwise configured to accommodate the positions of theinner conduit(s) and/or the flow transitions between the innerconduit(s) of the chamber 106 and the target fluid inlet 102 and targetfluid outlet 104. Both the end plates 110 and the end caps 112 may beconstructed of, for example, ABS plastic. In some implementations, apressure release valve 114 may optionally be provided to communicatewith the chamber 106 such that pressure may release from the chamber 106to, for example, a receptacle (not shown) adapted to communicate withthe pressure release valve 114 when the pressure in the chamber 106increases to a predetermined critical pressure. For example, if asyringe is used to admit the second endothermic reactant into thechamber 106 via the reactant inlet 108, the pressure release valve 114may be used to release any excess pressure in the chamber 106 resultingfrom utilization of the syringe. The use of a receptacle at the pressurerelease valve 114 maintains the cooling device 100 as a closed systemand ensures that the endothermic reactants remain isolated from theenvironment. Alternatively, element 114 may represent a fluid connectionto a flexible chamber that allows for expansion. As a furtheralternative, at least a portion of the chamber 106 may be flexible toallow for expansion. The chamber 106 may also be surrounded by aninsulating material (e.g., polypropylene foam covered in vinyl fabric)to ensure a minimum amount of heat transfer into the cooling device 100from the outside environment.

The cooling device 100 in FIG. 1 may be used to rapidly, effectively andreliably supply cooled fluids in a manner which does not require the aidof any other device. In one specific yet non-limiting example, thecooling device 100 may be utilized to quickly supply cooled salinesolution for intravenous administration to cardiac arrest patients inthe pre-hospital setting, so as to reduce the core body temperature ofthe patients. The cooling device 100 is completely isolated from theexternal environment, ensuring no contamination of the target liquid,any potential user, and any potential patient while the cooling device100 is in use. The cooling device 100 may also be utilized in variousother settings, e.g., stroke therapy and cardiac surgery. Moregenerally, the cooling device 100 may be utilized in a wide variety ofnon-medical as well as medical applications for cooling various liquids,gases, vapors, suspensions, etc. The cooling device 100 may be portable,easily storable and easily disposed of after use. The cooling device 100may be easily connected to input tubing and output tubing for use as anin-line device, as described in further detail below with respect toFIG. 7. The cooling device 100 according to the present teachings may bemanufactured in varying sizes and dimensions so as to allow for varioustemperatures of the target fluid at the target fluid outlet 104 of thecooling device 100. For example, reducing the length of the coolingdevice 100 may result in a higher temperature of the target fluid at thetarget fluid outlet 104 as a result of a decrease in surface areautilized for heat transfer. As another example, the cooling device 100according to the present teachings may be manufactured with varyingamounts of the first endothermic reactant so as to allow for varioustemperatures of the target fluid at the target fluid outlet 104 of thecooling device 100. As yet another example, different cooling devices100 according to the present teachings may be manufactured withdifferent endothermic reactants so as to allow for various temperaturesof the target fluid at the target fluid outlet 104 of the coolingdevices 100. In some implementations a target fluid flowing through thecooling device 100 may be cooled from room temperature down to about 3or 4° C. upon exit from the cooling device 100. The time required forthis amount of cooling to occur from the target fluid inlet 102 to thetarget fluid outlet 104 will depend on a variety of factors, includingfor example the volume of the chamber 106 and of the reactant loadedtherein, the internal diameter and length of the inner conduit(s) andthus the resulting flow rate and residence time of the target fluid inthe chamber 106, as well as the specific endothermic reactants utilized.

FIG. 2 is an exploded perspective view of an example of the fluidcooling device 100 discussed above. The fluid cooling device 100 may beutilized as described above with respect to FIG. 1, or as otherwisedescribed in the present teachings. The cooling device 100 also includesthe chamber 106 containing the first endothermic reactant. As anexample, during assembly the first endothermic reactant may be loadedthrough one of the initially open ends of the chamber 106. The coolingdevice 100 may also include an inner conduit 216 through which thetarget fluid flows from the target fluid inlet 102 to the target fluidoutlet 104 in thermal communication with, but fluidly isolated from, theendothermic reactants present in the chamber 106. The inner conduit 216may be configured to increase the surface area available for heattransfer. Thus, in the present example, the inner conduit 216 mayinclude one or more inner helical conduits 216. When the cooling device100 is assembled, the inner helical conduits 216 fluidly communicatewith the target fluid inlet 102 and the target fluid outlet 104, andprovide flow paths for the target fluid to be cooled. When the coolingdevice 100 is assembled, the chamber 106 surrounds the inner helicalconduits 216 as illustrated in FIG. 3. As an alternative to theillustrated helical configuration, the inner conduits 216 may have anyother suitable configuration, shape or profile that increases theirlengths, increases their outer surface areas, and/or maximizes theirthermal contact with the endothermic reactants.

In the present example, the inner helical conduits 216 may beconstructed of a thermally conductive material providing adequate heattransfer such as, for example, various metals, e.g., stainless steel,titanium, aluminum, or brass, and certain thermally conductive plastics.In some implementations, the inner helical conduits 216 may beconstructed of medical grade conductive materials to ensure againstcontamination of the target fluid for medical uses. If needed, theinside and/or outside surfaces of the inner helical conduits 216 may becoated with biocompatible or protective barrier films, as appreciated bypersons skilled in the art. When the cooling device 100 is assembled, anend plate 110 may be attached to the chamber 106 at each end of thechamber 106, and may be constructed to accommodate the ends of the innerhelical conduits 216 and support the inner helical conduits 216 in thechamber 106 in a fixed manner. For instance, in the present example inwhich three inner helical conduits 216 are utilized, each end plate 110may include three through-bores respectively communicating with thethree inner helical conduits 216 to facilitate flow-splitting from thetarget fluid inlet 102 and flow-merging to the target fluid outlet 104.An end cap 112 may also be secured by any suitable means (e.g., throughthe use of an adhesive) to the outside of the end plate 110 and/or thechamber 106 at each end of the chamber 106 when the cooling device 100is assembled. As also noted above, the chamber 106 may also besurrounded by an insulating material (not specifically shown) to ensurea minimum amount of heat transfer into the cooling device 100 from theoutside environment.

FIG. 3 is a cut-away view of a portion of the fluid cooling device 100.Specifically, FIG. 3 illustrates the three inner helical conduits 216 ofthe present example after installation in the surrounding chamber 106.In this example, the total amount of heat removed from the target fluidas it flows from the inlet side to the outlet side of the chamber 106,and the rate of heat removal, are increased by splitting the flow intomore than one inner conduit 216 and by coiling the inner conduits 216 soas to increase their lengths from inlet to outlet. The coiled or helicalshapes are but one example; other examples include serpentine shapes andvarious other multi-turn configurations. As another example, the innerconduits 216 may be provided with cooling fins. Generally, no limitationis placed on the internal diameter(s) of the inner conduit(s) 216, solong as target fluid flow therethrough is unimpeded and travel time issufficient to ensure a desired amount of heat rejection to thesurrounding chamber 106. It can also be seen in FIG. 3 that an amplevolume is provided around and between the inner conduits 216 for fillingthe chamber 106 with the selected endothermic reactants. Upon initiationof the endothermic reaction in the chamber 106, thermal gradients areestablished from the inner conduits 216 and outward in a multitude ofdirections.

FIG. 4 is a cross-sectional elevation view of another example of a fluidcooling device 400 according to the present teachings. As in theprevious example, the cooling device 400 includes a target fluid inlet102 and a target fluid outlet 104, which in this example include femaleand male Luer-type fittings, respectively. The cooling device 400 alsoincludes inner helical conduits 216 fluidly communicating with thetarget fluid inlet 102 and the target fluid outlet 104 and providingflow paths for the target fluid to be cooled. The cooling device 400includes a chamber 106 surrounding the inner helical conduits 216 andcontaining a first endothermic reactant. FIG. 4 also illustrates aninsulation layer 436 surrounding the chamber 106 which may be includedin the cooling device 400, as described above. The chamber 106 furtherincludes a reactant inlet 414 selectively alterable from a closed stateto an open state. In this example, the reactant inlet 414 includes afrangible or openable barrier 420 spanning the internal cross-section ofthe chamber 106. In the closed state, the barrier 420 may divide thechamber 106 into a first region 432 containing the first endothermicreactant (e.g., ammonium nitrate) and a second region 428 containing thesecond endothermic reactant (e.g., water). In the closed state, thefirst endothermic reactant is isolated from the second endothermicreactant by the barrier 420 and thus no endothermic reaction occurs.When the reactant inlet 414 is altered to the open state, such as bybreaking, puncturing or otherwise opening the barrier 420, an opening440 is created to provide a flow path for enabling the secondendothermic reactant to come into contact with the first endothermicreactant for initiating the endothermic reaction and cooling the targetfluid in the inner helical conduits 216. Alternatively, the firstendothermic reactant may flow from the first region 432 into the secondregion 428 and thus into contact with the second endothermic reactant.More generally, at least one of the reactants is flowable so thatinteraction among the reactants occurs after the opening 440 in thebarrier 420 has been formed.

In the present example, the barrier 420 may be opened by any suitableuser-actuated opening mechanism 424. For example, the mechanism 424 mayinclude a button or knob that, when actuated by the user (e.g., pressed,pulled, slid, rotated, etc.), actuates a puncturing device 438 thatbreaks the barrier 420 and hence alters the reactant inlet 414 to theopen state by creating the opening 440, which allows the first andsecond endothermic reactants to mix or combine within the chamber 106.As used herein, terms such as “mix” and “combine” encompass any type ofcontact or interaction between reactants that results in the endothermicreaction utilized as the cooling mechanism according to the presentteachings. The exact mechanics of the interaction between theendothermic reactants and the particular reaction kinetics will dependon the type of endothermic reaction conducted in a given implementation,one non-limiting example being the dissolution of certain nitrates orchlorides in a suitable solvent such as water as noted above. As anotherexample, the mechanism 424 may include or operate as a switch that, whenactuated by the user, moves the barrier 420 or a portion thereof (e.g.,a valve, shutter, or sliding mechanism) to an open state, therebycreating the opening 440 and allowing the second endothermic reactant toflow. In this latter case, the element 438 may represent any suitablemechanical linkage between the mechanism 424 and the barrier 420. Forinstance, the mechanism 424 may be linked to the barrier 420 such thatpushing or pulling the mechanism 424 translates or rotates all or partof the barrier 420 to create the opening 440. As another alternative,the mechanism 424 may be configured such that sliding the mechanism 424a short distance causes the barrier 420 to open in the manner of ashutter. In all of the foregoing alternatives, the term “breaking” asused in conjunction with altering the barrier 420 encompasses any meansby which the opening 440 may be created (e.g., puncturing, moving thebarrier 420 or a portion thereof, etc.), and thus in this context termssuch as “breaking” and “opening” are used interchangeably. Moreover, inconjunction with breaking or opening the barrier 420, the cooling device400 may be shaken or agitated by the user to promote the mixing of thereactants.

FIG. 5 is a flow diagram illustrating an example of a method for coolinga target fluid according to the present teachings. The method may beimplemented by utilizing a cooling device 100 or 400 such as describedabove and illustrated in FIGS. 1-4. The first step 502 in the methodgenerally includes flowing the target fluid through a target fluid inletinto an inner conduit or conduits of a cooling device. The target fluidmay include, for example, saline solution or any other fluid desired tobe cooled in a particular application. The cooling device of the presentexample may include a chamber surrounding the inner conduit andcontaining a first endothermic reactant (e.g., ammonium nitrate). Thechamber may include a reactant inlet that is selectively alterable froma closed state to an open state. The reactant inlet may be internal orexternal to the chamber as described above. When the reactant inlet isin the closed state, the first endothermic reactant is isolated from asecond endothermic reactant and no endothermic reaction occurs. Thesecond step 504 in the present example includes altering the reactantinlet from the closed state to the open state. Consequently, thereactant inlet provides a flow path for enabling the second endothermicreactant (e.g., water) to come into contact with the first endothermicreactant in the chamber for initiating the endothermic reaction andcooling the target fluid in the inner conduit. The target fluid may becooled to a temperature of, for example, 3 to 4 degrees Celsius, or avariety of other temperatures, depending on the particular applicationof the method. In some implementations, the second step 504 may beperformed prior to carrying out the first step 504, so as to allow thereaction to begin before flowing the target fluid through the targetfluid inlet. The third step 506 in the present example includes flowingthe target fluid through a target fluid outlet of the cooling device toa selected destination for the cooled target fluid such as into areceiving tube. In one example of one implementation of the presentteachings, the cooled-fluid-receiving tube may include IV tubing for usein the medical field.

FIG. 6 is a flow diagram illustrating an example of a method fortreating a patient according to the present teachings. The presentmethod may be used, for example, in the treatment of cardiac arrestpatients in the pre-hospital or in-hospital settings. The present methodmay also be used, as another example, in stroke recovery therapy. Thefirst step 602 in the method generally includes flowing a target fluidto be cooled from a reservoir. The target fluid reservoir may include,for example, an IV bag containing a suitable intravenous fluid such assaline solution, and which may additionally include a therapeuticallyactive drug if indicated for the specific situation. Alternatively, adrug may be added to the saline solution after the saline solution hasexited a cooling device. The second step 604 in the method includesflowing the target fluid through a target fluid inlet and into an innerconduit(s) of the cooling device, as described above in conjunction withFIG. 5. The third step 606 in the method includes altering a reactantinlet from a closed state to an open state, as described above. Asdiscussed above in conjunction with FIG. 5, the reactant inlet may bealtered from the closed state to the open state prior to flowing thetarget fluid through the target fluid inlet of the cooling device, so asto allow the reaction to commence prior to the target fluid entering theinner conduit(s) of the cooling device. The fourth step 608 in themethod includes flowing the target fluid through a target fluid outletof the cooling device into a cooled-fluid-receiving tube, as describedabove. The fifth step 610 includes administering to the patient thetarget fluid in the cooled-fluid-receiving tube intravenously until, forexample, a state of hypothermia is reached in the patient. Administeringthe cooled target fluid to the patient may include addingtherapeutically active drugs to the cooled target fluid. As anotherexample of an implementation of the present teachings, the fifth step610 may include administering the cooled target fluid to the patient tobegin induced hypothermia therapy in the pre-hospital setting, althougha state of induced hypothermia in the patient may not be reached untilthe patient is, for example, in the in-hospital setting. As yet anotherexample, the fifth step 610 may include intravenously administering thecooled target fluid to the patient in order to significantly reduce thecore body temperature of the patient, with or without the patient everreaching a state of hypothermia.

FIG. 7 is a schematic of an intravenous target fluid delivery system 700according to the present teachings. The intravenous target fluiddelivery system 700 includes an IV target fluid reservoir 702, a coolingdevice 704, and a cooled IV target fluid receiving tube 708. The IVtarget fluid reservoir 702 contains an IV target fluid to be cooled inthe cooling device 704. The IV target fluid reservoir 702 may include astandard IV bag, for example. The IV target fluid may include salinesolution, and the saline solution may include therapeutically activedrugs. The IV target fluid reservoir 702 fluidly communicates with atarget fluid inlet of the cooling device 704. The target fluid inlet maygenerally be configured to accommodate the size of any inlet tubing orfitting that fluidly couples the IV target fluid reservoir 702 to thetarget fluid inlet of the cooling device 704. The cooling device 704 maygenerally be configured as discussed above with respect to FIGS. 1through 4. For example, the cooling device 704 may include the targetfluid inlet through which the IV target fluid to be cooled may enter thecooling device 704, and a target fluid outlet through which the cooledIV target fluid may exit the cooling device 704, the target fluid outletbeing in fluid communication with the cooled IV target fluid receivingtube 708. The cooling device 704 includes a chamber surrounding one ormore inner conduits between the target fluid inlet and the target fluidoutlet, and contains a first endothermic reactant. The inner conduit(s)fluidly communicates with the target fluid inlet and the target fluidoutlet, and provides one or more flow paths for the IV target fluid tobe cooled. The chamber includes a reactant inlet that is selectivelyalterable from a closed state to an open state. In the closed state, thefirst endothermic reactant is isolated from a second endothermicreactant and no endothermic reaction occurs. In the open state, thereactant inlet provides a flow path for enabling the second endothermicreactant to come into contact with the first endothermic reactant in thechamber for initiating the endothermic reaction and consequently coolingthe IV target fluid in the inner conduit(s). In the present example, thesecond endothermic reactant may be flowed into the chamber via thereactant inlet by, for example, an external second endothermic reactantsupply 706 (e.g., a syringe or other external source of the secondendothermic reactant). Alternatively, the second endothermic reactantmay be provided internally within the cooling device 704 as describedabove in conjunction with FIG. 4. In some implementations, the firstendothermic reactant may not be preloaded in the chamber and may beflowed into the chamber via the reactant inlet by, for example, anexternal first endothermic reactant supply. The cooled IV target fluidreceiving tube 708 is configured for intravenously administering thecooled IV target fluid to a patient. The cooled IV target fluidreceiving tube 708 may include, for example, an IV catheter or any othersuitable IV fluid delivery device for administering the cooled IV targetfluid to the patient. Therapeutically active drugs may be added to thecooled IV target fluid prior to administering the cooled IV target fluidto the patient. The cooled IV target fluid may be utilized to reduce thecore body temperature of the patient. In one example, the cooled IVtarget fluid may be administered to the patient until the patientreaches a state of hypothermia.

In general, terms such as “communicate” and “in . . . communicationwith” (for example, a first component “communicates with” or “is incommunication with” a second component) are used herein to indicate astructural, functional, mechanical, electrical, signal, optical,magnetic, electromagnetic, ionic or fluidic relationship between two ormore components or elements. As such, the fact that one component issaid to communicate with a second component is not intended to excludethe possibility that additional components may be present between,and/or operatively associated or engaged with, the first and secondcomponents.

It will be understood that various aspects or details of the inventionmay be changed without departing from the scope of the invention.Furthermore, the foregoing description is for the purpose ofillustration only, and not for the purpose of limitation—the inventionbeing defined by the claims.

What is claimed is:
 1. A cooling device comprising: a target fluidinlet; a target fluid outlet; a plurality of inner conduits fluidlycommunicating with the target fluid inlet and the target fluid outlet,the plurality of inner conduits providing a plurality of respective flowpaths for a target fluid to be cooled; and a chamber surrounding theplurality of inner conduits and containing a first endothermic reactant,the chamber including a reactant inlet selectively alterable from aclosed state to an open state, wherein: in the closed state, the firstendothermic reactant is isolated from a second endothermic reactant andno endothermic reaction occurs; and in the open state, the reactantinlet provides a flow path for enabling the second endothermic reactantto come into contact with the first endothermic reactant in the chamberfor initiating the endothermic reaction and cooling the target fluid inthe plurality of inner conduits.
 2. The cooling device of claim 1,wherein the reactant inlet comprises a fitting configured for connectionto an external source of the second endothermic reactant.
 3. The coolingdevice of claim 1, wherein the first endothermic reactant comprises aninorganic salt.
 4. The cooling device of claim 3, wherein the secondendothermic reactant comprises water.
 5. The cooling device of claim 1,wherein at least a portion of each inner conduit is helical.
 6. Thecooling device of claim 1, wherein the reactant inlet comprises abarrier and in the closed state, the barrier divides the chamber into afirst region containing the first endothermic reactant, and a secondregion containing the second endothermic reactant.
 7. The cooling deviceof claim 6, further comprising an actuator configured to open thebarrier wherein the reactant inlet is altered to the open state.
 8. Thecooling device of claim 7, wherein the actuator is configured topuncture the barrier.
 9. The cooling device of claim 7, wherein theactuator is configured to move at least a portion of the barrier tocreate an opening therethrough.
 10. An intravenous target fluid deliverysystem comprising: an IV target fluid reservoir including an IV targetfluid to be cooled; a cooling device including: a target fluid inletfluidly communicating with the IV target fluid reservoir; a target fluidoutlet; a plurality of inner conduits fluidly communicating with thetarget fluid inlet and the target fluid outlet, the plurality of innerconduits providing a plurality of respective flow paths for the IVtarget fluid to be cooled; and a chamber surrounding the plurality ofinner conduits and containing a first endothermic reactant, the chamberincluding a reactant inlet selectively alterable from a closed state toan open state, wherein in the closed state, the first endothermicreactant is isolated from a second endothermic reactant and noendothermic reaction occurs, and in the open state, the reactant inletprovides a flow path for enabling the second endothermic reactant tocome into contact with the first endothermic reactant in the chamber forinitiating the endothermic reaction and cooling the IV target fluid inthe inner conduit; and a cooled IV target fluid receiving tube fluidlycommunicating with the target fluid outlet, wherein the cooled IV targetfluid receiving tube is configured for intravenously administering thecooled IV target fluid to a patient.
 11. The intravenous target fluiddelivery system of claim 10, wherein the IV target fluid comprisessaline solution.
 12. The intravenous target fluid delivery system ofclaim 11, wherein the IV target fluid further comprises atherapeutically active drug.
 13. The intravenous target fluid deliverysystem of claim 10, wherein the reactant inlet comprises a fittingconfigured for connection to an external source of the secondendothermic reactant.
 14. The intravenous target fluid delivery systemof claim 10, wherein the reactant inlet comprises a barrier and in theclosed state, the barrier divides the chamber into a first regioncontaining the first endothermic reactant, and a second regioncontaining the second endothermic reactant.
 15. The intravenous targetfluid delivery system of claim 14, further comprising an actuatorconfigured to open the barrier wherein the reactant inlet is altered toan open state.
 16. The intravenous target fluid delivery system of claim10, wherein the cooled IV target fluid receiving tube includes an IVcatheter.